Newton's Law of Motion Problem, HELP :'(

1. The problem statement, all variables and given/known data
Assume a 8-passenger learjet has a force of gravity of 66000 N [down] acting on it as it travels at a constant velocity of 640 km/hr [W]. if the forward thrust provided by the engines is 13000 N [W], determine:

a - the upward life force on the plane
b - the force due to air resistance on the plane

2. Relevant equations

3. The attempt at a solution
i have absolutely no clue on how to even begin, im so lost. please help, thanks.